The only indication Kensington Palace has provided is that Meghan is due to give birth in spring 2019, which would be April, May or June next year.

Now Australian singer Missy Higgins, who met Meghan and Harry in Sydney on Tuesday, has let slip exactly how far along the Duchess of Sussex is in her pregnancy.

“What an honour to meet the beautiful Duchess today! She was such a sweetheart. I said I felt sorry for her having to do all these meet-and-greets while four months pregnant! What a trooper,” the 35-year-old singer wrote.

Your read that right, four months.

This would mean Meghan is due to give birth in late March/early April, a year after Prince William and Kate Middleton welcomed Prince Louis this year.

Meghan and Harry, who tied the knot in May, kicked off their Australian tour on Tuesday in Sydney with visits to Taronga Zoo and the Opera House, as well as an afternoon reception hosted by the Governor-General at Admiralty House.

According to Missy, Meghan Markle is four months pregnant as she and Prince Harry kick off their Australian tour. Photo: Getty

It was there that Missy had the chance to meet Meghan and Prince Harry, and she even took her two-month-on daughter Luna along for the royal meet and greet.